Judges 11:38-42

Then he said, “Go.” So he let her go for two months; and she left with her friends, and wept on the mountains because of her virginity.

And at the end of two months she returned to her father, who did to her what he had vowed; and she had no relations with a man. And it became a custom in Israel,

that the daughters of Israel went annually to commemorate the daughter of Jephthah the Gileadite for four days in the year.